The present disclosure relates generally to imaging systems and in particular to three-dimensional (3D) object detection, tracking and characterization using optical imaging.
Motion-capture systems are used in a variety of contexts to obtain information about the conformation and motion of various objects, including objects with articulating members, such as human hands or human bodies. Such systems generally include cameras to capture sequential images of an object in motion and computers to analyze the images to create a reconstruction of an object's volume, position and motion. For 3D motion capture, at least two cameras are typically used.
Image-based motion-capture systems rely on the ability to distinguish an object of interest from other objects or background. This is often achieved using image-analysis algorithms that detect edges, typically by comparing pixels to detect abrupt changes in color and/or brightness. Adequate illumination of the object of interest is obviously key to successful detection. For systems operative over a broad detection space, high illumination intensities are typically necessary; in effect, the entire monitored region is bathed in light (which may be visible or outside the visible spectrum, e.g., infrared radiation), so that “worst case” object positions receive sufficient illumination. This means that the unitary light intensity is almost always greater than necessary, imposing excessive requirements in terms of hardware design, the number and/or luminance of lighting elements, and power consumption.